Wireless local area networks (WLANs) conforming to specifications in the Institute of Electrical and Electronics Engineers (“IEEE”) 802.11 family typically involve a basic service set (BSS) managed by a device acting in the role of an access point (AP). Each BSS may be identified by a service set identifier (SSID), such that a wireless communications device using a WLAN protocol may receive broadcast messages or beacons from access points within range advertising the SSID of their associated networks. The wireless communications device may then manually or automatically select the one or more of the detected networks and perform an association process to create one or more communications links. In order to identify suitable access points and thereby utilize available WLANs, a wireless communications device may perform scans on the wireless channels of one or more frequency bands. Existence of available networks may be determined passively by spending a period of time on a WLAN channel to receive any beacons that are periodically broadcast by APs operating on that channel or actively by sending a probe request that triggers a probe response sent by an AP receiving the transmission. The scanning process may be used to find usable networks prior to association or may be performed as a background process after associating with one network to determine the availability of alternative networks that may have more desirable characteristics. Scanning may also be performed to assess channel conditions and profile network characteristics.
Accordingly, a wireless communications device may spend a considerable amount of time to complete a comprehensive scan of the available wireless channels. During this time, the transceiver of the wireless communications device may be devoted to the scanning process and unable to perform other operations. As such, it would be desirable to decrease the amount of time devoted to the scanning process to free the transceiver for other tasks. Further, since the wireless communications device must be in active mode rather than a power saving mode when performing the scanning process, a significant amount of energy consumption may also be involved. Particularly for battery powered mobile devices, it would be desirable to minimize the amount of energy used by a wireless communications device to obtain information about nearby access points.
In light of these goals, this disclosure provides systems and methods to facilitate the scanning process, such as by identifying available networks more quickly. These and other aspects are described below in the materials that follow.